Alternating-direct-current system of control.



R. P. JACKSON. ALTBRNATING DIRECT CURRENT SYSTEM OF CONTROL. APPLICATION FILED DEC. 18, 1905. RENEWED MAR. 15, 1909'.

967,389. Patented Aug. 16, 1910.

4 BHEETS-SHBET 1.

INVENTOR WITNESSES: a

R. P. JACKSON. ALTERNATING DIRECT CURRENT SYSTEM OF CONTROL. nrmornon FILED DEG. 1a, 1905. RENEWED MAR. 15, 1969.

Patented Aug. 16, 1910.

4 8HEETS-SHEET 2.

k INV TOR fi b g7 (OJ- 15. BY

TURNEY R. P. JACKSON. ALTEBNATING DIRECT CURRENT SYSTEM 0? 001mm. APPLICATION FILED DEO.18, 1905. RENEWED MAR. 15, 1909. 967,389, Patented Aug. 16, 1910.

4 BHEETB-SHEET 3.

' r NVENTOR @114 m4 v 2 q 1 4 v ATTORNEY R. P. JACKSON.

ALTERNATING DIRECT GURRENT SYSTEM OF CONTROL. APPLICATION FILED DEU.18, 1905. RENEWED MAR. 15, 1909.

967,389. 1 Patented Aug. 16, 1910.

4 SHEETS-SHEET 4.

2/6 ZNVENTO R ATTRNF UNITED STATES: PATENT OFFICE.

m r. :rAcxsoN, or wrnxmsnune, PENNSYLVANIA, AssreNon rowns'rmonousn ELECTRIC a MANUFACTURING comrANY, A CORPORATION or PENNSYLVANIA.

AL'rnaNA'nNe-mancr-cUnnnN'r SYSTEM or Common Patented Aug. 16, 1910.

Application fil ed December 18, 1905, Serial No. 282,285. Renewed March 15, 1909. Serial No, 488,638.

To all whom it may concern:

Be it known that I, RAY'P. JACKSON, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a ated by either alternating or direct currents.

The object of my invention is to provide a system of control for devices of the above specified character whereby the control or auxiliary circuits of'the system may be supplied automatically with alternating or direct current and whereby the circuit relations of the motors may be adjusted automatically in accordance with the character of energy that may be supplied from the distributing circuit.

Since the development of a commutator type of alternating current motor which may also be operated satisfactorily by direct current, it has become desirable to equip electric railway vehicles therewith, and articularly such vehicles as are employ in interurban service, as the vehicles may then be operated in cities and towns upon existing direct current systems and by alternating current in rural districts, where greater efiiciency in long distance transmission may be obtained by the use of alternating current than by direct current and the expense of the transmission system be thereby reduced.

Alternating currents may be transformed efliciently from one voltage to another by means of very simple and comparativelyinexpensive apparatus and may consequently be transmitted over a railway system at a high voltage and be utilized by the motors at a low voltage, while the means for effecting voltage transformation of direct currents are complicated and expensive and can be utilized only when thefchange of potential is small. It follows, therefore, that direct currents are usually applied to the motors at the transmission voltage.

It has generally been found most expedient to arrange the motors in different circuit relations when operated by alternating currents than when operated by direct currents; for instance, when a vehicle is provided with four motors, the motors may conveniently be, connected in series-parallel relation when operated by alternating currents and in series relation when operated by direct currents.

My invention provides means whereby the control or governing circuits of the system may be supplied automatically with the same character of energy as that derived from the distributing circuit.

It also provides means whereby the circuit relations of the motors may be changed automatically as the character of the energy supplied to the system is changed.

Other features of novelty will be noted more specifically hereinafter and in the appended claims.

Figure 1 of the accompanying drawings is a diagrammatic view of a complete system embodying my invention. Fig. 2 is a diagrammatic view, upon an enlarged scale, of the control or auxiliary circuits of the system shown in Fig. 1. Fig. 3 is a diagrammatic view of the motor circuits of the system shown in Fig. 1. Fig. 4- is a simplified diagrammatic View of the conditions of the motor circuits when sup lied with direct currents. Fig. 5 is a simi ar view of the motor circuits when supplied with alternating currents. Fig. 6 is a simplified diagrammatic view showing the arrangement of the cut-out switches and the conditions of the motor circuits when direct currents are supplied to the motors, and Fig. 7 is a similar view illustrating the conditions when alternating currents are supplied to the motors.

The system comprises among its important elements two pairs of motors having armatures 1, 2, 3 and 4 and field magnet windings 5, 6, 7 and 8; a reversing switch 9; a change-over switch 10, the principal function of which is to arrange the circuit relations of the motors in accordance with the character of the energy that may be supplied thereto; a main resistance device 11; a transformer 12; a plurality of switches 13, 14, 15, 1(5, 17 and 18 that are adapted to govern the amount of the resistance 11 or the active length of the winding of the transformer 12 that may be included in the motor circuits; an overload relay switch 19 that causes the switches 13 to 18, inclusive, to open when more than a predetermined amount of current is supplied to the motors and that therefore prevents closure thereof until the reversing and change-over switches compared with that 0 have been returned to their initial positions; cut-out switches 20, 21 and 22; impedance or inductive resistance windings 23 and 24; an auxiliary ohmic resistance device 25 that is connected in series with and between the inductive resistance windings 23 and 24; another device 26 of comparatively high Ohmic resistance that is connected in shunt circuit to the devices 24 and 25; a choke-coil 27, train conductors 28, 29, 30, 31, 32 and 33 that may extend through a train comprising a plurality of vehicles that are severally equipped with the system; a, master switch. 34 for controlling operation of the reversing switch and a master switch35 for controlling operation of the switches 13 to 18, inclusive. The circuits are adapted to be supplied with either alternating or direct current from a trolley conductor 36 and a grounded return conductor or track rail 37 that may be supplied with energy either from an alternating current generator 38 or from a direct current generator 39, or from other suitable sources;

The ohmic and inductive resistances of the devices 23, 24, 25 and 26 are so adjusted with reference to each other that most of the potential drop in the circuit occurs inthe ohmic resistance devices 25 and 26 when direct currents are supplied to the system, and in the inductive resistance windings 23 and 24 when alternating currents are supplied to the system. The desired relation may be secured, as .will readily understood, by making the windings 23 and 24 of low ohmic resistance and high inductive resistance and by so designing the devices 25 and 26 that they shall possess only ohmic resistance, that referably large as e device 25.

The reversing switch 9 is maintained in the position shown by means of centralizing springs 40 and operation'thereof to the left and to the right, respectively, 'forthe purpose of arrangin the circuits of the motors for forward and. reverse rotationv is'controlled by means of magnet \vindin 41 and 42, one terminal of each of which is of the device 26 being connected to the grounded return conductor or track rail 3? and the other terminals of wh ch are ada ted to be connected to a point 43 in the auxi iary resistance 25 by means of the master switches '34 and 35.

The ma et windings 41 and 42 are so constructe that onl very small amounts of current are require to energize them, and it has generally been found necessary to apply higher alternating than direct current volta es thereto in order to cause the require amounts of current to traverse the wmdings. It is well understood that when only asmall amount of current is derived from a circuit in shunt to a resistance, the voltage applied to the shunt circuit is very nearly equal to the diflerence of potential which would exist between the points in the "resistance to which the shunt circuit is connected if no such circuit were established. Consequently, the voltage which is applied to the magnet windings 41 and 42 when direct current is supphed to the system is very nearly equal to the difference of potential which would otherwise exist between the'point 43 in the resistance device 25 and the grounded conductor 37. When alternating current is supplied to the system, the voltage applied to the windin s 41 and 42 will be but little more than t e difference of potential existing between the terminals of the inductive winding 24, because only a small portion of the drop of potential then occurs in the ohmic resistance device 25.

winding1 23 is fifty ohms, that of the device 7 25 one undred and fifty ohms, that of the device 26 two thousand ohms and that of the winding 24 so small as to be practically negligible the amount of current which will traverse the device 25 is 2.45 amperes and the drop of potential therein is three hundred and sixty-eight volts. If the resistance of the circuit between the point 43' in'the device 25 and the grounded conductor 37 is 16.3 ohms, and of the circuit in shunt thereto is two hundred ohms, the drop in voltage over the two circuits is about thirty-seven volts and the current in the shunt circuit is .185 am res, while the drop in potential which won d occur between the point 43 and the grounded conductor would be forty volts if no circuit existed in shunt thereto. The magnet windings may, of course, be constructed so that they will become energized when .185 amperesor less'traverse them.

The inductive resistances of the devices 23 and 24 may be such that when alternatin current is supplied to the system, drops 0 potential of two hundred and seventy-five and two hundred voltsflrespectively will occur therein, the remaining twenty-five volts of drop occurring in the resistance device 25.

Then approximately two hundred volts are pose of arranging the circuits for operating comes a the motors by direct and alternating currents, respectively, is eifected by magnet windings 45 and 46. One terminal of each of the windings 45 and 46' is connected to the track rail 37 and the remaining terminals are connected respectivel to a point 47 in the auxiliar resistance. evice 26 and to junction 48 0 the terminals of the inductive and non-inductive resistance devices 24 and 25.

It will be observed that the magnet winding 45 of the change-over switch is supplied with direct current from the resistance device 26 in a manner similar to that in which the windings 41 and 42 of the reversing switch are su plied from the resistance device 25, and the magnet windin 46 is sup-' plied with alternating current rom the inductive resistance winding 24 in a manner similar to that in which the windings 41 and 42 are also supplied therefrom, and the modes of operation are in all respects similar.

The switches 13 to 18, inclusive, are governed in their operation by means, of magnet windings 51, 52, 53, 54, 55 and 56, respectively, the circuits of which are adapted to be controlled manually by the master switch 35 and automatically by means of an interlocking switch 57 that is operated by the reversing switch 9, an interlocking switch 58 that is o erated by the changeover switch 10, inter ocking switches 59, 60, 61, 62, 63 and 64 that are operated respectively by switches 13 to 18, inclusive, and by means of the overload relay switch 19. It will be observed that the magnet windings 51 to 56,

- inclusive, are connected between conductors 65 and 66, the interlocking switches 57 and 58 being located in the circuit of the former and the overload relay switch 19 being located in the circuit of the latter, and that they are otherwise supplied with energy in the same manner as the magnet windings 1 and 42 of the reversing switch. The interlocking switch 57 prevents the supply of energy to the magnet windings 51 to 56, inclusive, until the reversing switch has be n moved to either its forward or reverse position, and the interlocking switch 58 also prevents energizing of the magnet windings 51 to 6, inclusive, until the chan e-over switch has arranged the circuits of t e motors for operation thereof by either alternating or direct currents.

The overload relay switch 19 isoperated by means of a magnet winding 67 that is so arranged in circuit with the motors that elusive, and

when the current supplied thereto exceeds a predetermined amount the switch 19 will be caused to open, thereby interrupting the circuits of the magnet windings 51 to 56, in-

ermitting: the switches 13 to 18 to open. X magnet windin 68, the terininals of which are conneete respectively the point 43 in the resistance device 25 and the other terminal is connected directly to the point 69 in the inductive winding 24, from which it is seen that it is arranged in a shunt circuit to a portion of the resistance device 25 and of the inductive winding 24.

The interlockin switches 59 to 64, inclusive, are provide for the purpose of permitting the switches 13 to 18,.inclusive, to

close only in a predetermined order, the

manner in which these switches operate belarly from Fig. 2, and since they orm no part of my present invention, I deem it unnecessary to explain their operation in detail, it being onl necessar to state the order of closure 0. the switc es.

When the master switch 35 is moved to position a, the switches 13 and 15 are first closed and then switches 14 and 1.5. From the simplified diagram of the motor circuits of Figs. 4 and 5, it is seen that upon closure of the switches 13 and 15, the motors are connected in circuit between the rounded conductor 37 and either terminal 0 of the resistance device 11 or a point 71 in the.

transformer 12, according as the changeover switch is in position to arrange the circuits of the motors for operation by direct or by alternating current, the resistance 72 being included in circuit therewith. Upon closure of the switches 14 and 15 and opening of the switch 13, the resistance 72 is removed from the motor circuit. If the master switch 35 is moved to position b, the

switches 14 and 16 will first close and then the switches 13 and 16. NVhen the switches 14 and 16 are closed, the motors are counected either to a point 73 in the resistance device 11 or to a point 74 in the transformer 12 with the resistance 72 included in the. circuit, the latter beingv removed from the circuit when the switches 13 and 16 are closed. When the master switch is moved to (position 0, switches 13 and 17' are closed an then switches 14 and 17, and when it.

occupies osition (Z, the' switches 14 and 18 are first c osed and then switches 13 and 18,

the circuits being altered in each case in a manner similar to what has just been described for the positions a. and b as will be readily understood from consideration of Figs. 4 and 5. The function of the resistmg evident from the drawings and articutransformer winding 12 are connected in 1 conductin closed circuit by reason of simultaneous closure of successive switches and It serves the additional function of a resistance in the motor circuit.

When the magnet winding 45 is energized in the manner which has been described hereinbefore, the segments of the chan eover switch that are located upon the 0t and dash lines D-C are brought into enagement with the corresponding contact fingers and a circuit is established from the trolley conductor 36, through conduct ng segment 75, resistance device 11, conducting segment 76 (if the master switch 35 occupies the position a),switch 15, resistance 72, switch 13, magnet winding 67 of the overload relay switch 19, blade 77 of the cutout switch 22, conducting segment 7810f the reversin switch, field magnet windings 5 and 6 of t e motors, conducting segment 79 of the reversing switch, armatures 1 and 2 of the motors, blade 80 of the cut-out switch 22, conductin segment 81' of the change-over switch, b ade 82 of the cut-out sw1tch 20, segment 83 of the reversing s'witch, fie d magnet windings 7 and 8, conducting segment 84 and armatures 3 and 4, to the grounded conductor 37. Thus, the motors are connected in series with the resistances 1-1 and 72 in circuit,-as shown in Fig. 4, the latter being removed from the circuit as the switches 13 to 18, inclusive, are closed in the hereinbefore stated order.

In Fig. 6-is shown a simplified dia ram of the motor circuits when .connecte for direct current operation and with the cutout switches roperly arranged therein, from which it is seen that if the'switch 22 is moved to the positionshown in broken lines, the motor armatures 1 and 2 and) field magnet windings 5 and 6 are removed from the circuit and a circuit established through the blades 77 of the switch 22 in the position shown in broken lines, blade 85 of switch 20, the blade 80 of the switch 22,'blade 82 of the switch 20, field magnet windings 7 and 8 and armatures 3 and 4. If the switch 20 is moved to the position shown in broken lines, a circuit may be established through the blade 77 of the switch 22, field magnet 5 and 6, and motor armatures 1 windings and 2, lade 80 of switch 22 and blade 82 of switch 20 in the position" shown in broken lines, the motor armatures 3 and 4 and field magnet windings 7 and 8 being thereby removed from the circuit.

When the magnet winding .46 is energlzed, the change-over switch 10 is operated so as to bring the conducting segments that are located upon the dot and dash lines {i0 into engagement with the corresponding contact fingers, and the motors are connected in series-parallel relation withan equalizing connection between the junctions of the armature windings with the field ma et windings, as illustrated in Fig. 5. ThlS will be best understood by tracing the circuit from the trolley conductor 36,'conducting segment 86 of the change-over switch and transformer winding 12, to track rail 37. The motors are then connected in a circuit from a point 71 in the transformer winding 12, conducting segment 87 of the change-over switch, switches 15 and 14 (if the master switch occupies the position a) and magnet winding 67 of the overload relay switch 19, to a pomt 88, where the circuit divides, one portion traversing conducting segment 89, blade 82 of cut-out switch 20,

segment 83 of the reversing switch (it the master switch 34 is operated so asto electrically connect the corresponding uppermost contact fingers), field magnet Wll'ldings 7 and 8, conducting segment 84 of the reversin switch and armatures 3 and 4, to the track rail 37. i The other portion of the circuit from the point 88 traverses blade 77, the cut-out switch 22, conducting segment 78 of the reversing switch, field magnet windings 5 and 6, conducting segments 79 of the reversing switch, armatures 1 and 2, blade 80 of cut-out switch 22 and conducting segment 89 of the change-over'switch, to the track rail 37. It will thus be seen that the motor armatures 1 and 2 and field magnet windings 5 and 6 are connected in series and also the motor armatures ,3 and 4 and field magnet windings 7 and 8, and that the two pairs of motors are arranged in parallel, all as shown in Fig. 5. An equallzing connection. is also made between the terminal 90 of the armature 1, which traverses a circuit through cut-out switch 21 and conducting segment 91 of the change-over switch, to terminal 92 of the armature 3.

Fig. 7 is a simplified diagram illustrating the conditions of thecircuits for alternating current operation with the cut-out switches properly arranged therein, from which it will be seen that if the switch 22 is moved to the position shown in broken lines and the switch 21 opened, the motor armatures- 1 and 2 and field magnet windings 5 and 6 are entirely removed from the circuit and the equalizing connection between the terminals of the armatures of the motors 1 and 3 is interrupted. If it is desired to remove the motor armatures 3 and 4 and field ma et windings 7 and 8 from the circuit, switc 20 should be moved to the position shown in broken lines and' the switch 21 opened, whereby the circuit is interrupted at the terminal of the field magnet winding 7 and the equalizing connection between the terminals of the armatures 1 and 3 is broken.

In practice, the transmission system will I prising a. plurality of cars may move di-- rectly from a section which is supplied with direct current to an adjacent section which is supplied with alternating current, or vice versa, and it may occur that when a train passes from one section to another, some of the cars will be su plied with direct current and the others witii alternating current. In such cases, it is evidently necessary that the positions of the several change over switches shall correspond to the character of the energy that is supplied to the respective cars to which they pertain, and I accordingly connect the choke-coil 27 between the train conductor 33 and the point 43 in the resistance device 25, in order to prevent the supply of alternating current through the train conductors from a car that is being operated by alternating current to the magnet winding of the change-over switch of another car which-is being supplied with direct current.

'For'instance, if alternating current is being supplied to the car which is equipped with the complete system shown in. Fig. 1 and direct current is supplied to the next car in the rear, the control system of which is only artially shown, it will be observed that ii it were not for the choke-coils 27 and 27 alternating current might be supplied from the point 43 in the resistance 25, through the choke-coil 27, train conductor 33, choke-coil 27, resistance 25 and inductive winding 24, a suflicient voltage being thereby impressed upon the inductive wind-' ing 24 to cause an operating voltage to be applied to the terminal of the controlling magnet winding d6 of the changeover switchon that car, thus causin the circuits of the motors to be arranged or the reception of alternating current while direct ourrent'is being supplied to the car.

The devices which have been illustrated in the drawings are only representative of any suitable means which may be employed for the pur oses described, and it is consequently un erstood that the magnet windings which, as here shown, operate directly the devices to which they pertain may only serve to control the ositions thereof, as by governing the supp y of fluid-pressure or other means for operatin the devices. The inductive resistance windings 23 and 24 may be placed upon difierent magnetic cores, as shown in Fig. 1, or upon the same core, as shown in Fig. 2. -It will also be'understood that the change-over switch may be constructed so as to arrange the motors in any other desired circuit relations than those shown and described, and that the system may be employed to control other translating devices than motors that are adapted for operation by either direct or alternating current.

In two other applications, Serial Numbers and 292,236,' respectively, filed by circuit with two of the first name and a chan e-over switc circuits of t e translating devices for operame of even date herewith, I have shown and described systems of control which difier from that herein disclosed in certain particulars that will be evident from a conslderation thereof. 1

I claim as my invention:

1. The combination with circuit conductors for supplying either alternating or direct current energy, translating devices, a reversing switch, and a change-over switch for arranging the circuits of the translating devices, of controlling magnet windings for said switches each having a terminal connected to one of the sup ly conductors, two inductive resistances and one non-inductive resistance connected in series with each other and with the non-inductive resistance be tween the inductive resistances, a second non-inductive resistance arranged in arallel resistances means for connectin the reversing switch controlling magnet windings between apoint of the first non-inductive-resistance and a supply conductor, and connections between the remaining terminals of the change-over switch controlling magnet wind- 1ngs and points respectively of the second non-inductive resistance and of one of the lnductive resistances. I

2. The combination with conductors for supplying either alternating or direct current energy, of a plurality of independently operated units each of which comprises translating devices, a reversing switch, a change-over switch for arranging the circuits of the translating devices, controlling magnet windings for said switches, each having a terminal connected to one of the supply conductors, two inductive resistances and one non-inductive resistance connected in series with each other and with the noninductive resistance between the inductive resistances, a second non-inductive resistance arranged in parallel circuit with two of the first named resistances, means for connecting the reversing switch controlling .trolling magnet windings and points respectively of the second non-inductive resistance and of one of the inductive windings, conductors that connect corresponding ,oints in the circuits pertaining to the di' erent units, and inductive windings that are 1nter- )osed in the connection between the points inthe smaller resistance to which terminals of the reversing switch controlling magnet windings are connected.

3. The combination with a source of direct currents, a source of alternating currents, translating devices a reversing switch,

h for adjusting the 1 ranged in parallel circuit with the'first noninductive resistance and one of said inductive windings, the changeover switch controlling magnet windin bein arranged in parallel circuit respect sely t3 one of the,

inductive windings and to a portion of'the second non-inductive resistance, and means for connecting the reversing switch controlling magnet windings in parallel circuit to one of the inductive windings and a portion of the first non-inductive resistance.

The combination with a source of direct currents, a source of alternating currents, translating devices, a reversing switch,

a a change-overswitch for adjusting the cirsuits of the translating devices for operation thereof by either characteroi energy, and a set of switches for further adjusting the circuits of the devices, of controlling magnet windings for the switches, two inductive windings, a non-inductive resistance cuits o magnet windings for the switches,

that is arranged between and in series cirsuit with the inductive windings, a second non-inductive resistance arranged in parallel circuit withjthe first non-inductive resistance and one "of the inductive windings,

the change-over switch controlling magnet windings being arranged in parallel circuit respectivelyto one of the inductive windings to a portion of the second non-inductive resistance, and means .for connectin the magnet windings of the reversing switch and of the switches of the set in parallel circuit to one of the inductive windings and a portion or? the first non-inductive resistance.

5. The combination with a source of direct currentaa source of alternating currents, translating devices, a reversing switch, a chan e-over switch for adjusting'the cirthe "translating devices for operation thereof by either character of energy, and. a set otswitches for further adjusting the circuits ofithe devices, of controlling two inductive windings, a non-inductive resistance that is arranged between and in series circuit with the inductive windings, a second non-inductive resistance arranged in parallel circuit withthefirst non-inductive resistance and one of the inductive windings, the cha?e -over switch controllin ma et win mg respectively to one o the inductive windin s and to a portion of the second nonin native resistance, means for connectin 3 the magnet windings of the reversing switc and o'fthe switches oithe set in arallel circuit to one of the inductive win ings and a portion of the first non-inductive resistance,

in series resistance and s being arran ed in para lei circuitand means for preventing operation of the switches of the set until after operation of the reversing switch.

6. The combination with a source of direct currents, a source of alternating currents, I translating devices, two inductive resistances,

a non-inductive resistance that is connected between and in series circuit with said inductive resistances, and a second non-inductive resistance that is arranged in parallel circuit with two of the other resistances, of

means tor arranging the circuits of the translating devices for operation thereofby j either character of energy, and controlling 1 means therefor that is supplied with energy from circuits in parallel respectively to one of the inductive resistances and to a portion of the second non-inductive resistance.

7. The combination with a source of di- .rect currents, a source of alternating currents, translating devices, two inductive i'esistances, a non-inductive res stance that is connected between and in series circuit therewith, and another non-inductive resistance that is arranged in parallel circuit with two of the other resistances, of means for arrangoperation thereof by either characterot .en-

ergy, controlling means therefor that is supplied with energy from circuits in parallel respectively to one of the inductive resistances and to a portion of the second noninductive resistance, means for further arranging the circuits of the translating devices, and controlling means therefor that is suippliedwith energ from a circuit in paral el to a portion 0 the first non-inductive ancesf i '8. The combination with a source of alternating currents, a source of direct currents,

a plurality of sets of translating devices,

meansror arranging the circuits of the translatin devices in'each set in accordance with the c aracter of the energy that may be utilized, automatic controlling means therefor, and means for preventing suficient amounts of the non-corresponding character of energy being conducted from the circuits of one set of the devices to the circuits of the other tocause operationof the said automatic controlling means.

9. The combination with circuit conductors for supplying either alternatin or direct current energy, a plurality o translatin devices and a plurality of change-over switc es for arranging the circuits of the translating devices, of magnet windings for controlling operat on thereof thatmay be energized respectively by alternating and direct currents, and "means for preventing operative amountsoi alternatin current from being supplied; to the control ing windings that are specially adapted to direct current operation and vice versa.

' ing' the circuits of the translating devices for v one of the inductive resist- 10. The combination with circuit conductors for supplying either alternating or direct current energy, a plurality of translating devices and a plurality of change-over swltches for arranging the circuits of the translating devices, of magnet windings for controlling the operation thereof that may be energized respectively by alternating and direct currents, and means for preventing operative amounts of alternating current from being supplied to the controlling windings that are specially adapted to direct current operation, and vice versa,

when a part of the translating devices are being supplied with direct current and the remainder With alternating current.

11. The combination with circuit conductors for supplying either alternating or direct current energy, a plurality of translating devices and a plurality of change-over switches for arranging the circuits of the translating devices, of magnet windings for controlling the operation thereof that may be energized respectively by alternating and direct currents, and one or more choke-coils for preventing operative amounts of alternating current from being supplied to the controlling windings that are specially adapted to direct current operation.

12. The combination with-circuit conductors for supplying either alternating or direct current energy, a plurality of translating devices and a plurality of change-over switches for arranging the circuits of the translating devices, of magnet windings for controlling the operation thereof that may be energized respectively by alternating and direct currents, and one or more choke-coils for preventing operative amounts of alternating current from being supplied to the controlling windings that are specially adapted to direct current operation when a part of the translating devices are being supplied with direct current and the remainder with alternatin current.

In testimony whereof, I have hereunto subscribed my name this 15th day of December, 1905.

RAY P. JACKSON. Witnessesz.

O'r'ro S. SGHAIRER, BIRNEY HINES. 

